1. Field of the Invention
The present invention relates, in general, to electrical power service to homes and buildings and, more specifically, to watthour meters, meter sockets and watthour meter socket adapters.
2. Description of the Art
Electrical power is supplied to an individual site or service by electrical power line conductors located above or below ground. In a conventional arrangement, electrical power line conductors are connected to contacts in a watthour meter socket mounted on a building wall. Electrical load conductors are connected to another set of contacts in the meter socket and extend to the electrical distribution network in the building. A watthour meter, typically of the plug-in, socket type, is connected to the contacts in the meter socket to measure the electrical power drawn through the load conductors.
Plug-in watthour meter socket adapters and socket adapters/extenders, both hereafter referred to simply as socket adapters, are designed to plug into the meter socket housing contacts. Such socket adapters are employed to convert ringless style sockets to ring style sockets or to extend the mounting position of the jaw terminals in the socket housing outward from the socket housing for mounting various electrical equipment, such as test devices or survey recorders, in the socket housing.
Such socket adapters employ a generally annular base having a shell joined thereto and extending outward from one side of the base. Contacts are mounted in the shell and base. Each contact has a female jaw portion disposed interiorly within the shell and a male blade terminal connected to the female jaw portion and extending outward from the shell and the base for a plug-in connection to the terminals in the meter socket housing.
While it is typical for a watthour meter, once it is installed in a socket or socket and socket adapter, to remain in service for many years, it is still necessary for such meters to be removed for repair or replacement from time to time as well as to temporarily disconnect electrical service to a particular customer. During the installation and removal of the watthour meter from the socket or socket adapter, the electric power line terminals in the socket or socket adapter remain connected to the electric utility power line conductors and carry potential. The utility employee installing or removing the watthour meter may inadvertently touch such contacts thereby raising the possibility of injury. Furthermore, an inadvertent short across the contacts caused by a tool contacting the contacts or a full fault caused by a 90xc2x0 offset insertion of the meter can cause a spark or flash which could damage the watthour meter installation as well as posing a significant risk of injury to the utility employee.
In U.S. Pat. No. 5,577,933, a unique safety shield for a watthour meter mounting apparatus is disclosed which completely covers all of the exposed portions of the jaw contacts to prevent inadvertent contact with such contacts by the utility employee or by a tool.
One embodiment of this safety shield is in the form of a housing having a unitary sidewall and top wall defining a closed body with an internal recess surrounding the jaw contacts. Narrow apertures or slots are formed in the top wall for receiving the blade terminals of a watthour meter therethrough into engagement with jaw contacts disposed immediately below each aperture in the top wall of the safety shield. In another embodiment, a plurality of receptacles extend from a planar wall mountable in the socket adapter, with each receptacle having one or more slots for receiving the meter blade terminals therethrough. The individual receptacles are sized to completely surround at least one jaw contact in the socket adapter.
Improved versions of Applicants"" safety shield as shown in U.S. Pat. Nos. 5,572,386 and 5,577,933 and co-pending patent applications Ser. No. 09/291,885 filed Apr. 14, 1999. These safety shields have been designed for a snap in connection to the socket adapter base by means of legs having clip end portions which snap through apertures formed in the base wall of the socket adapter housing.
While such safety shields simplify the assembly of the safety shield in the socket adapter and reduce costs by eliminating separate fasteners previously used to mount safety shields in a socket adapter, it is possible that the removal of a watthour meter from the jaw contacts in a socket adapter could cause the safety shield to disengage from the socket adapter housing thereby exposing the jaw contacts in the socket adapter housing which are connected to the live line jaws in the meter socket. What is needed is a safety shield for a watthour meter socket adapter which resists separation from the socket adapter housing upon watthour meter removal from the socket adapter.
In another aspect of watthour meter usage, watthour meters are frequently provided with three to four foot long cables or conductors for telephone and other communication signals. The cables extend outwardly from the watthour meter and must be carefully placed within the socket adapter housing away from the watthour meter jaws so as not to be pinched or broken by the watthour meter blades upon insertion of the watthour meter blade into the socket adapter jaws or between the watthour meter feet and the bottom wall of the socket adapter housing.
One prior art approach employs a plurality of snap clips mounted by screws to the sidewall of the socket adapter housing, typically near the joint between the sidewall and the base of the socket adapter housing. The watthour meter cables are wound behind the snap clips in a circle about the inner periphery of the sidewall. Even though this apparatus has the added cost of mounting three or four snap clips within the socket adapter housing, it does provide storage of the watthour meter cables where the socket adapter housing has a standard 2xc2xd inch sidewall depth.
However, the low profile socket adapter housing pioneered by the Assignee of the present invention has a significantly shorter or reduced sidewall height which limits space within the interior of the socket adapter housing for wire storage.
The actual telephone connection from the watthour meter cable to an external telephone line are made through a telephone connector, such as a telephone line connector sold under the trademark EDCO by Liebert Corp., Model No. FAS-TEL-200T. This connector also provides telephone line surge suppression. One or more standard telephone jacks are mounted at one side portion of this telephone connector. A second telephone jack along an opposite side edge of the connector is capable of receiving the telephone jack on the end of the watthour meter cable. Typically, the second jack is prewired to separate ring and line terminals within the connector.
Thus, it would be desirable to provide a safety shield for use in a watthour meter socket adapter and/or meter socket which is easy to use, includes integral wire wrap means, is suitable for use in all types of socket adapters including low-profile socket adapters, and provides a simple telephone connector and telephone line connections.
The present invention is an improved electrical service apparatus safety shield.
The safety shield of the present invention provides several unique advantages not found in previously devised electrical service apparatus or watthour meter safety shields. First, the safety shield for the present invention is uniquely formed with mounting legs to provide a secure snap-in connection of the safety shield to an electrical service apparatus, such as a watthour meter socket adapter, which resists dislodgement of the safety shield upon removal watthour meter from the socket adapter. The safety shield also provides integral wire wrap means for convenient, easy-to-use storage of watthour meter communication cables and for other conductors extending from the watthour meter. This integral mounting of the wire wrap means on the safety shield reduces assembly time and manufacturing costs of a watthour meter socket adapter as the separate spring clips employed in prior art socket adapters are eliminated. Finally, the safety shield of the present invention has a low height thereby enabling it to be used in a low-profile socket adapter while still providing the easy wire wrap and telephone interconnection features
In one aspect, the safety shield is an electrically insulating shield for covering substantially all of the exposed portions of the electrical contacts within the housing of the watthour meter socket or socket adapter, the shield having apertures alignable with at least one electrical contact for receiving a blade terminal of a watthour meter therethrough in engagement with the one electrical contact. Preferably, four mounting legs are provided on the shield, each releasibly engaged with edges of an aperture in the socket adapter housing. Latch members are mounted on the end of each leg and non-movably latch through one aperture to the housing to prevent disengagement of the safety shield from the socket adapter during removal of the watthour meter from the socket adapter.
Each latch member is in the form of L-shaped clip having first and second angularly disposed sides which non-movably fill one aperture in the housing.
In another aspect of the invention, the safety shield carries wire wrap members for receiving cables and conductors extending from a watthour meter. The wire wrap members are arranged in at least one pair and, preferably, a plurality of pairs in the spaced locations about the safety shield.
In a specific aspect, the wire wrap members include a first leg extending outward from the shield, a second leg extending angularly from one end of the first leg and terminating in a tip. The tip is spaced from the edge of the shield to define an opening within the first and second legs and the shield for receiving a wire therein. Preferably, the tip end is disposed at an angle from the second leg to aid in retaining the wound cables and conductors within the arm.
In another specific aspect, the wire wrap members two spaced flanges extending outwardly from opposite sides of the shield. Preferably two flanges are carried on the shield, one between each pair of arms.
In yet another specific aspect, the wire wrap members include an aperture formed in the socket adapter housing and a clip carried on the shield and having an end portion cantilevered over the aperture, the center clip and functioning as a strain relief for a wire extending through the aperture in the shield.
In yet another aspect, the shield includes a light transmissive means or guide having first and second ends, the first end adapted to be disposed in proximity with a light generating source within the socket adapter to transmit light generated by the light generating source to the second end, the second being end disposed in a visible position to make the light visible externally of the socket adapter housing. Preferably, the second end of the light transmissive means is disposed through or visible through an aperture in the sidewall of the socket adapter housing.
The improved safety shield of the present invention adds new functionality to electrical service apparatus safety shields. In addition to providing the basic insulating protection for the service apparatus jaw contacts, the safety shield of the present invention also is provided with unique latch members which resist separation of the safety shield from the service apparatus or socket adapter housing during the removal of a watthour meter from the socket adapter. At the same time, the latch members can still be disengaged from the rear of the socket adapter to remove the safety shield from the socket adapter after the socket adapter is disengaged from the meter socket.
The unique provision of wire wrap members directly on the safety shield provides a simple and inexpensive wire wrap capability for conductors and cables attached to watthour meters in a simple and inexpensive manner. As the wire wrap members are carried directly on the shield, the need for separate mounting of spring clips and fasteners at various locations within the socket adapter housing is eliminated. Further, the position of the wire wrap members on the safety shield ensures that the wound cables and conductors are disposed in the non-interfering locations with respect to the watthour meter blade terminals and the watthour meter feet to prevent any damage to or breakage of the conductors and cables.
The provision of a unique light transmissive means or guide on the safety shield of the present invention uniquely enables light generated by a light generating source, such as an LED, in a functional circuit mountable within the socket adapter, to be transmitted to a more easily visible position, such as externally of the socket adapter. This enables the function indicated by the light generating source to be easily detected exteriorly of the socket adapter without requiring removal of the socket adapter from the watthour meter socket.